Automobile-truck differential mechanism



E. M. STEHNBERG. AUTOMOBILE TRUCK DIFFERENTIAL MECHANISM.

APPLICATION FILED "OM19. I918.

Patented Mar. 23, 1920.

2 SHEETS-SHEET I- INVENTOR jmrf ATTO NEY WITNESS 4;;

E. M. STERNBERG. AUTOMOBILE TRUCK DIFFERENTIAL MECHANISM. APPLICAHGNFILED NOV-19.1918.

1 ,334, 325 Patented Mar. 23, 1920,

2 SHEETS-SHEET 2 ATTORNEY the differential, which UNITED STATES PATENTOFFICE.

AUTOMOBILE-TRUCK DIFfERENTIAL MECHANISM.

Specification of Letters Patent,

Patented Mar. 23, 1920.

Application. liked November 19, 1918. Serial No. 263,151.

"lb all "(rho/n it may concern Be it known that I, Enxs'r M. STERN--BERG, a citizen of the United States, and resident of West .Allis, inthe county of Milwaukee and State oi \Visconsin, have invented certainnew and useful Improvements in Automobile-Truck Differential Mechanism;and I do hereby declare that the following is a full, clear, and exactdescription thereof.

My invention relates to new and useful improvements in the powertransmitting systems of automobile trucks, and is more particularlydirected to the provision of an nn roved differential mechanism.

E1 the operation of an automobile truck, in any other power systemutilizing an internal combustion engine for its source of power, it ishighly desirable to procure, when traveling, a constant operation of theengine under the full load conditions for which it is designed, inaccordance with the established principles of engine operation.Considerable diflicult has heretofore been enmuntered, particu arly withrespect to automobile trucks of the heavier type, in maintainingconstant load conditions of the engine in the various uses of the truck.As an example of the variation of load, apart from conditions of grade,it may be noted that a seven ton truck weighs approximately 10000 lbs.and the total load of a truck would thus vary from this weight when. thetruck is empty, to a Weight of 24000 lbs., when the truckis fullyloaded.

It is therefore primarily the object of my invention to provide means inan automobile truck for the maintcnanm of an even lead upon the engineunder the widely variant operative conditions of the truck tothusprocure a maximum conservation of,0il, fuel and wear of the motor parts,and it is more particularly an object to provide an exceedingly widerange of the power ratio by the provision of a variable speed connectionfor coacts therewith in a most compact and efiicient manner.

A further object incidental to the accomplishment of the foregoing mainobject resides in the provision of an arrangement wherein a doublereduction of power may be procured in the diflerential mechanism.

y A still further objectresides in the provision of an arrangementwhereby the propcller shaft of the power plant may be dis connected fromthe dilicrcnlial mechanism to prevent back driving of the propellershaft incidental to coasting of the truck.

A still further object residcs in the provision of a braking nrraugementassociated. with the dill'ercnl'iul, which affects a maximum brakelevcl'ngc.

still furthcr object resides in the provi sion of an arrangement whereinthc lorcgoing advantages may be embodied in a dill'ereutial mechanism ata minimum increase of manui'ncturing cost over couvcntionnl types ofdifferential mechanisms and propeller shaft connections therewith, andit is a more detailed object in this connection to utilize thedifferential end housing mom bers as selective drive gears for thedili'crcutial mechanism.

\Vith the above and other objects and advantages in view, which wil beapparent as the description proceeds. my invention rcsides in the novelfeatures of construction, combination and arrnng'em *ut of parts ashereinafter described and defined by the op )ended claims.

n the acconipanyinp drawings:

Figure 1 an elerationul view of a aria.- hle speed dilferentialmechanism mnbodying my invention.

Fig. 2 is a vertical sectional view therethrough on the line 2-: of Fig.l,

Referringnow more particularly to thc accompanying drawings, 5 and (idesignate respectively upper and lower sections of the casing of myimproved difl'orenl'ial, the upper section having a bearing extension 7for the propeller shaft 8 of the power plant, While. the ends of thelower casing sections are extended to form axle housings 9. The uppercasing section 5 carries the conventional depending ring portions 10 inwhich are mounted bearing castings ll for a pair of wheel drive shafts12 extending through the axle housings. The bearing castings l1 mountbearing rollers 13 which engage on outwardly projected sleeves 14carried by end housing members 15 of the differential mechanism.

This differential mechanism is of the Well known lockingtype, embodyingWorm gear wheels 16 on the ends of the wheel drive shafts 12 which meshwith worms 17 carried by a housing annulus 18 which is secured betweenthe end housing members '15 by bolts 19 passed through said members and(ill - and constitute gear wheels of different sizes whereby either oftwo difl'erinr rotative speeds may be imparted to the iflerentialmechanism. A jack shaft 22 is mounted in bearing blocks 23 secured tothe upper main.

casing section 5, and a 1pair of gear wheels 24 and 25 of relatively areprovided, having a common hub por tion splined on the .jack shaftwhereby either of the gear wheels may mesh with the correspondinghousing ear wheel 15, or whereby both gear when may lie ,between thehousing gear Wheels in neutral position. The gear wheels 24 and 25 areshifted by a rod 26 having spanner connection 27 with sairlgear wheels,said rod being yieldably held in its various positions by a conventionalspring deteut 28. One end portion of the jack shaft is enlarged infrusto conical form to receive a beveled gear wheel 29 keyed on saidenlarged portion and held in lace by a nut 30 t readed on the shaft= Itively large size and meshes with a smaller gear wheel 31 on the end ofthe propeller shaft.

An exceedingly simple, compact and efiicient arrangement has thus beenprovided whereby the number of gear ratios of the ordinary transmissionare doubled to thus provide an adequate range for the exceedmgly variantload conditions encountered in true s of the heavier type as heretoforeexplained.

It is thus seen that my greatl increased ran e of gear ratios isprocurer in an excee ingly compact manner, departing to a. minimumextent from conventional automobile truck design and thus permitting theembodiment of my invention in conventional truck structures at a minimumadded cost, it being particularly noted that the two speed gears of thedifferential form the conventional housing ends of said mechanism andcoact in procuring a structure of maximum simplicity. It is observedthat when one of the gears 24 is in mesh with its corresponding housinggear 25, the others gears are out of mesh, thus preventing Wear. Also.it is noted that when the gears 24 and 25 are in neutral position, therotation of the wheel drive shafts 12 in cidental to coasting of thevehicle will not betransmitted to the propeller shaft and maintransmission connections. The jack shaft 22 is extended from the maincasing and carries a wheel 34 which may be used either for taking offpower, or as a brake,

and it is noted that a maximum brake learge and small size,

his beveled gear wheel is of relaverage is thus attained by reason ofthe leverage reduction between the gears 24 and 25 and theircorresponding housing gears 1.5. It is further notedthat a doublereduction of the gear ratio is procured in the present arrangement bythe different Sizes of the coaeting sets of gears, this double re,-duction being rocured in a manner utiliz ing the essential elements toprocure the variable drive of the differential.

Also, the variable driveof the differential is procured by the sim leaddition of an extra pair of gears an a splined connection on the partswhich must be provided in a sin le speed structure. Hence, I avoid theaddition of bearings and all extra parts entailing a complicatedlubricatin system in the differential, it being noted t at none of theparts of my improved mechanism are superimposed or require clutchconnections other than the simple clutch effected b shifting the doubleear out of mesh wit either of the gears 1%.

My improved structure has minimum frictional resistance, which is anexceedingly important consideration in view of the heavy loads of anautomobile truck.

What is claimed is:

l. A mechanism of the class described including a pair of shafts, adifferential mechanimn for said shafts including end housing memberssurrounding the shafts and provided with peripheral series of-gearteeth, a jack shaft. and gears on said ack shaft selectively engageablewith the gear' teeth of the differential mechanism.

2. A mechanism of the class described including a pair of shafts,combined gear wheels and housing members on the adjacent end portions ofthe shafts, an annulus disposed between and secured to said combinedgear wheels and housing members, difi'erential gear members, m0unted insaid annulus, gear members on the shafts meshing therewith, a jackshaft, and gears on said jack shaft selectively engageable with thecombined gear wheels and housing members.

, 3. A mechanism of the class described including a main casing, bearingmembers in the casing, a pair of shafts extending through said bearingmembers, combined gear wheels and end housing members having sleeveportions engaged in said bearing members of the main casing, an annulusdisposed between and secured to said combined gear wheels and endhousing members, difvided with peripheral series of gear teeth, a, jackshaft, and a double gear splined on the jack shaft and provided with anintermediate annular groove, :1 gear shifting member engaged in saidgroove, said double gear member having two series of gear teeth adaptedfor selective engagement with the said gear teeth of the differentialmechanism and being adapted for disposition between the series of gearteeth of the difi'er- 10 enter] mechanism in a position free for contactwith the gear teeth thereof.

In testimony that I claim the foregoing T have hereunto set my hand atMilwaukee,

in the county of Milwaukee and State of 15 hsconsin.

ERNST M. STERN BERG.

